Field of the Invention
The invention relates to an oil filter with a bypass valve and with a cover, the cover having an orifice. The invention also relates to an oil tank with an oil filter of this type.
The bypass valve of an oil filter serves to prevent the filter from collapsing or bursting under heavy load due to impurities. When the pressure in the filter rises to a specific value below the failure point of the filter, the bypass valve opens, with the result that oil can escape and flow around the actual filter element. A contaminated filter element is relieved in this way.
In order to indicate the contamination of a filter, an indicator device for a filter is known from U.S. Pat. No. 3,545,616. There, the indicator device has a shank which is connected to the bypass valve and which extends through the housing of the filter. A laterally extending indicator part is provided, connected to the shank, and has wings and serves for displaying various color strips of the indicator device, depending on the position of the bypass valve. The indicator device known from the said U.S. Pat. No. 3,545,616 has a relatively complicated construction and, because of this, is complicated in terms of production and is susceptible to faults during operation.